3,514 research outputs found
Quantum motion of a neutron in a wave-guide in the gravitational field
We study theoretically the quantum motion of a neutron in a horizontal
wave-guide in the gravitational field of the Earth. The wave-guide in question
is equipped with a mirror below and a rough absorber above. We show that such a
system acts as a quantum filter, i.e. it effectively absorbs quantum states
with sufficiently high transversal energy but transmits low-energy states. The
states transmitted are mainly determined by the potential well formed by the
gravitational field of the Earth and the mirror. The formalism developed for
quantum motion in an absorbing wave-guide is applied to the description of the
recent experiment on the observation of the quantum states of neutrons in the
Earth's gravitational field
Universal long-time properties of Lagrangian statistics in the Batchelor regime and their application to the passive scalar problem
We consider transport of dynamically passive quantities in the Batchelor
regime of smooth in space velocity field. For the case of arbitrary temporal
correlations of the velocity we formulate the statistics of relevant
characteristics of Lagrangian motion. This allows to generalize many results
obtained previously for the delta-correlated in time strain, thus answering the
question of universality of these results.Comment: 11 pages, revtex; added references, typos correcte
- …